Magnus Adlam is under no illusion as he watches a truck and trailer unit reverse down the Karāpiro Dam road from the spillway carpark.
“That should sort the men out from the boys,” he says as the trailer’s load – a new 40-tonne water intake gate – edges closer to a crane waiting on the north-eastern side of Ariki Street.
Magnus Adlam keeps an eye on the dam gate’s progress to its new home behind him. Photo: Mary Anne Gill.
Cambridge News – July 18, 2024
Adlam, Mercury’s Operation Readiness coordinator, recalls the time three years ago when a truck and trailer, not dissimilar in size, got stuck on the single lane concrete arch bridge dam road.
See: Karapiro dam bridge blocked
So, there is no room for error, precision is the name of the game, he says.
“That piece there is probably one of the most important parts of the dam. When everything goes wrong, up here somewhere or down there, it’s a big valve that stops the water coming in.”
Two and a half hours later, the job is done, the emergency dam gate is in its place having been loaded by crane into a cradle on the trailer from the spillway carpark and taken along the road where another crane gently slotted it into place in the dam.
All being well the gate – eight metres wide, six metres high and 0.75 metres deep – will stay there for years protecting one of the dam’s three new generators.
It was the second milestone in Mercury’s $90 million upgrade at Karāpiro Hydro Power Station on Waikato River.
The gate is loaded into the cradle on the truck and trailer unit. Photo: Mary Anne Gill.
Three new power generation units housing hydro turbines which make electricity from the river’s force will provide an additional five megawatts, enough for 19,000 homes.
The third one should be in place next year and Ariki Street dam road reopened to the public.
“It’s a refurbishment in the truest word. From 32MWs to 37MWs. With new technology and design, you get more bang for your buck,” says Adlam, who has worked at Karāpiro for 15 years.
“With the same amount of water, we can generate more electricity.”
His job in the future will be keeping an eye on any maintenance issues, such as replacing the seals in the gate.
Norconsult engineers, from left Dean Hassall, Chris Lucas and Kristen Kwo ready for the gate they designed to go into place at Karāpiro Dam. Photo: Mary Anne Gill.
Three engineers, who previously worked for Norwegian company Norconsult and now operate as contractors, can be seen from the Karāpiro Dam Lookout smiling with relief.
Earlier Dean Hassall, Chris Lucas and Kristen Kwo told The News the work involved in designing the dam gates. Each gate took six people about a year to fabricate in Palmerston North.
“The horizontal beams are full of holes to let air out and water in,” says Lucas, who also mentions his parents did their courting at Karāpiro in the late 1940s.
The three new gates are far superior in hydraulic design compared to the original gates, which were installed more than 75 years ago.
“Design has advanced a lot since then,” says Kwo.
Another interested onlooker was local Fiona Soanes who was taking her dog for a walk when she saw the cranes in action.
She and her late husband moved to Karāpiro from Wellington 14 years ago.
“There’s always activity going on here. It’s a great area,” she says as the rain pummels down helping to feed Karāpiro Dam.
Mercury has nine hydro stations on the Waikato River – Karāpiro, Maraetai, Ōhakuri, Arapuni, Whakamaru, Aratiatia, Waipāpa, Ātiamuri and Taupō – producing about 10 per cent of New Zealand’s electricity.
See: Dam road shut
A reversing truck and trailer move the new dam gate towards the crane which manoeuvred it into place in the Karāpiro Dam. Photo: Mary Anne Gill.
This 40-tonne intake gate is now in place to protect one of three new generators at Karāpiro. Photo: Mary Anne Gill.
